Hydraulic fluid feed mechanisms that lead into a rotating shaft mounted in a transmission housing are known in a multitude of designs. For example, DE 199 21 749 A1 describes a hydraulic fluid feed mechanism that feeds into a primary shaft of a variable speed belt gear of a continuously variable, automatic transmission. The primary shaft is mounted on a bearing in a transmission housing. A bearing bore extending through the wall of the transmission housing in the area around the bearing is planned. The bearing is mounted axially in the transmission housing with a sealing ring. An electric-hydraulic control device is provided to supply hydraulic fluid to the variable speed gear; this device is oriented perpendicularly to the bearing bore on the end surface of the transmission housing and simultaneously serves to cover the bearing bore in the transmission housing. The supply of hydraulic fluid from the electric-hydraulic control device into an axial bore in the primary shaft is accomplished by a plain conduit system, in which two tubes, one inside the other, are inserted into a variable stage bore of the electric-hydraulic control device creating an oil-tight connection; both tubes extend into the axial bore in the primary shaft, and each of the two tubes is sealed against the rotation of the primary shaft by a sleeve bearing. The outer tube is axially fastened to the electric-hydraulic control device by a retaining panel. The inner tube is not secured in any way.
In DE 199 32 339 A1, of the applicant is a hydraulic fluid feed mechanism for a variable speed gear shaft of a continuously variable transmission became known, in which the supply of hydraulic fluid by a hydraulic transmission control device is accomplished by hydraulic feed lines located within a transmission housing, and by hydraulic feed lines located in a housing cover, into an axial variable bore in the variable speed gear shaft. The variable speed gear shaft is mounted in the transmission housing on at least one bearing, wherein the bearing is positioned within a corresponding bearing bore in the transmission housing and is fastened axially in this bearing bore by a retaining panel. The bearing bore is designed as a through bore into which the variable speed gear shaft extends. The bearing bore[hole] is covered by the housing cover. A tubular projection from the housing cover extends into the axial variable bore of the variable speed gear shaft, and is sealed against the rotating variable speed gear shaft by a rectangular-section ring. The hydraulic fluid is fed from a channel in the transmission housing into a channel in the housing cover that runs parallel to the shaft; from there it is fed into a boring in the housing cover that is oriented perpendicularly to the shaft and from there into a boring in the housing cover that is oriented perpendicularly to the shaft and, finally, by an inner axial boring in the tubular projection of the housing cover into the variable speed gear shaft. A flat packing seals the hydraulic fluid channels in the partition between the transmission housing and the housing cover from the outside.
The object of the present invention is to further develop a hydraulic fluid feed mechanism leading from a hydraulic or pneumatic transmission control device into a shaft of a transmission, especially for applications in which the pressure discharge from the hydraulic or pneumatic transmission control device to the shaft does not take place in the immediate vicinity of the shaft, while taking into consideration seal tightness problems, especially at high pressures.
Base on the known state of the art, the hydraulic fluid mechanism feeding into the shaft of a transmission comprises a hydraulic or pneumatic control device by which the hydraulic feed mechanism can be filled with hydraulic fluid; a transmission housing in which the shaft is positioned, and a housing cover, which is equipped with feed bores by which the hydraulic fluid is introduced into the shaft by the hydraulic or pneumatic control device.